For example, Japanese Patent Application Laid-Open Publication No. 10-41492 discloses a conventional solid state imaging apparatus. A sectional view of this solid state imaging apparatus is shown in FIG. 13. Legend 101 denotes a printed circuit rigid board made of a material such as ceramics or glass epoxy. Legend 104 denotes a pedestal made of a material such as resin for fixing an optical lens and an optical filter. Legend 105 denotes a cap made of a material such as resin for fixing the optical lens. The fixing pedestal 104 and the fixing cap 105 form a frame 113. Legend 106 denotes an optical lens made of a resin such as acryloyl. Legend 107 denotes the optical filter made of a material such as resin or glass. Legend 108 denotes a diaphragm, 109 denotes a solid state imaging element, 111 denotes a wire bond electrode connection portion, 201 denotes a printed circuit flexible board, and 203 denotes an external connection terminal.
Operation of the conventional solid state imaging apparatus will now be explained. Light which passes through the diaphragm 108 passes through the optical lens 106, and then passes through the optical filter 107. This light then falls on an imaging area of the solid state imaging element 109 where an image is formed. Video information of thus formed image is converted into electric signal, electrically coupled to the printed circuit rigid board 101 via the wire bond electrode connection portions 111, and further electrically coupled to the printed circuit flexible board 201 connected to the printed circuit rigid board 101. The electric signal is taken out from the external connection terminal 203 provided on the printed circuit flexible board 201.
Thus, in the conventional solid state imaging apparatus, the wire bond electrode connection portions 111 are required for the electric connection between the solid state imaging element 109 and the printed circuit rigid board 101.
However, because the wire bond electrode connection portions 111 are required, it is necessary to keep a space for the wire portions. As a result reduction of the thickness and size of the apparatus is thus disadvantageously limited.
Considering the thickness reduction of the printed circuit rigid board 101 itself and housing thereof into the case, the attempt to use the printed circuit flexible board 201 has been made. However, for reasons of the position precision securement of the optical lens and the solid state imaging element, stability in the case against vibration or the like, or the poor work efficiency at the time of mounting the solid state imaging element on the board, a rigid board made of glass epoxy or ceramics is used as the board in at least the portion for attaching the solid state imaging element thereto. As shown in FIG. 13, the printed circuit flexible board 201 is joined to the printed circuit rigid board 101 separately by soldering or the like.
However, heat generated by soldering or the like is conveyed to the solid state imaging element 109 via the printed circuit rigid board 101. Thus there is a fear that a color filter mounted on the pixel area of the solid state imaging element 109 will be degraded.
Furthermore, in order to reduce the size of the solid state imaging apparatus, the space of a connection land for connecting the printed circuit rigid board 101 to the printed circuit flexible board 201 becomes necessary. The area of the connection land must be made small as far as possible. In addition, if soldering is performed, it is difficult to perform the connection work with high precision and it takes time to perform the connection work. Even if an automatic connection device is utilized, soldering which does not convey heat to the color filter is needed. Even if, for example, laser heating, light beam heating, pulse tool heating, constant tool heating using robot control, or the like is introduced, therefore, the connection work takes a long time. In addition, a test for determining whether the connection work has been conducted securely becomes necessary. Therefore, a series of these processes takes a long time. This results in a great cost problem.